This invention relates to a measuring circuit device including a measuring circuit and a display associated with the circuit, and more particularly to an improved measuring circuit device provided with performance test means for notifying an operator whether or not the device is in a normal condition.
A measuring circuit device including a measuring circuit which measures an object and an associated display for displaying measured data is well known, wherein when a power switch is turned on the measuring circuit device immediately moves to a measuring ready mode without entering a self-performance testing mode so as to display measured data. The conventional measuring circuit device, however, has the disadvantage that if the measuring circuit is operating abnormally, it provides the display with incorrect measured data without notifying an operator that the displayed data is erroneous. The operator cannot know whether the data appearing on the display is correct or incorrect. As a result, the conventional measuring circuit device is disadvantageous with respect to its measuring reliability.
It is, therefore, a primary object of this invention to provide a measuring circuit device including testing and measuring modes, which performs a self-permance test in the testing mode so as to notify an operator operating the device whether or not the device is in a proper operating condition prior to the measuring mode.
It is a further object of this invention to provide a measuring circuit device including display testing means for testing the performance of a display and performance testing means for testing the performance of the device before measurements commence.
It is another object of this invention to provide a measuring circuit device which automatically performs a reference measurement so as to provide an improved precise measurement.
It is still another object of this invention to provide a measuring circuit device having a reduced power consumption.
According to this invention, there is provided a measuring circuit device comprising measuring circuit means, display means associated with the measuring circuit means for displaying data generated from the measuring circuit means, display test circuit means for testing the display by the display means, performance test circuit means associated with the measuring circuit means for actuating the measuring circuit means to display predetermined reference measured data by the display means, switching means for initiating operation of the device, switching circuit means responsive to actuation of the switching means for actuating the display test circuit means and the performance test circuit means, and for, in a predetermined time period, initiating a measuring operation by the measuring circuit means.
Other objects, features and the advantages of the measuring circuit device according to this invention will become apparent from the following detailed description of the invention provided in connection with the accompanying drawings, in which: